The Most Expensive House and Senate Races of 2012

In their race for the Massachusetts Senate seat, Brown (above) and Warren spent more combined than in any other race in the country.

The 2012 elections reached new heights in terms of the resources invested by outside groups, though some of the most expensive races of the cycle saw relatively small third-party expenditures.

But resources invested by outside groups greatly affected the overall cost of individual Congressional contests, even as that money proved not to be the determining factor in the outcome of every race. In California’s 52nd District, one of the costliest House races in the country, the outside spending slightly surpassed candidate spending, doubling the total cost of that campaign.

There are several ways to tabulate the cost of each race.

For this list, CQ Roll Call used the outside group spending figures for each race tracked by the Center for Responsive Politics and added the total disbursements (as of Nov. 26) filed to the Federal Election Commission by only the Democratic and Republican general election candidates. (One race featured two Democrats, thanks to California’s new primary format.) Outside group expenditures include funds invested by the congressional campaign committees, super PACs and political activist groups.

The following are the Top 5 most expensive House and Senate races, according to CQ Roll Call’s formula.

This state likely would have been ranked near the top for outside spending overall if not for a pledge signed by Brown and Warren that helped keep much of the noise away. But that hardly had an effect on spending here, as Warren and Brown spent more combined than in any other race in the country. And it appeared to still be competitive heading into the final week of campaigning: Each candidate spent more than $5 million after Oct. 17.

In a state not competitive in the presidential contest, this race was the biggest game in town. Despite Brown’s strengths as a candidate and his ability to attract moderate Democrats, he could not overcome the Democratic bent of the state and Obama’s strong showing. In Mitt Romney’s home state, the president won with 61 percent of the vote and by a margin of more than 700,000 votes, and Warren walked away with an 8-point victory.

Virginia: Democrat Tim Kaine vs. Republican George Allen

Candidates: $31,080,417

Outside: $49,891,298

Total: $80,971,715

The open-seat race to replace retiring Democratic Sen. Jim Webb was second only to the presidential among federal races that received the most outside spending. The nearly $50 million spent by national party campaign committees and other outside groups is reflective of both the competitiveness of the race and the costly media markets here in one of the newest swing states in the country.